Needle-orifice flow regulators are well known in the art. They are used for accurate valves of gases and liquids and particularly for small amounts. One particular use thereof is in Joule-Thomson crycooler. A description of cryocoolers is given in the Chapter 2 (pages 12-46) of Miniature Refrigerators for Cryogenic Sensors and Cold Electronics, GRAHAM WALKER (Clarendon Press-Oxford 1989). Conventional Joule-Thomson cryocoolers typically include a conduit receiving pressurized cooling fluid and a cooling fluid outlet nozzle. These cryocoolers also include a regulator for governing the rate of cooling fluid escape from the conduit via the outlet nozzle. The regulator includes a needle which is arranged for a variable position relative to the outlet nozzle and a temperature responsive apparatus to which the needle is attached for positioning the needle relative to the nozzle as a function of temperature. After an initial cool down stage, steady state flow regulation is provided by very slight movements of the needle which require only application thereto of very small forces. When the needle is attached to the positioning apparatus, even a slight distortion in the regulator, or any frictional resistance to movement of the needle by the outlet nozzle causes a lack of repeatability of conventional Joule-Thomson cryocoolers both in manufacture and in operation. As a result, they suffer from considerably lower gas utilization efficiency than could be expected from an ideally regulated cooler, and their operating specifications call for replacement at time intervals which are much shorter than desirable.